Twelve nations (Britain, France, Belgium, Netherlands, Italy, Portugal, Denmark, Iceland, Norway, U.S. and, Canada) sign the North Atlantic Treaty to form the North Atlantic Treaty Organization, an anti-Soviet defensive league for mutual assistance against aggression in North Atlantic. On 24 August, NATO was established by the US, Canada and 10 other Western nations, agreeing that an armed attack against one or more would be considered an attack against all.
Richert, Lucas Paul. "North Atlantic Treaty Organization founded". The Literary Encyclopedia. First published 01 October 2008
[http://www.litencyc.com/php/stopics.php?rec=true&UID=3205, accessed 23 May 2013.]